Excel 2007 : LOOKUP and SUM issue

I have a spreadseet where I have multiple results for a LOOKUP_VALUE and I want to get a sum of all the values several columns over. I have to do this with a large amount of data in multiple spreadsheets

i.e. I want a sum of all the fields 2 columns over from the value 'C', which in this case would be a total value of 70

C 12 13 15 4
D 12 11 15 4
C 12 16 15 4
A 12 9 15 4
C 12 28 41 4
C 32 13 15 4
B 12 13 15 4

Any help would be greatly appreciated!